Embryonic development and differentiation is controlled, directly and indirectly, by changes in the patterns of gene expression. It is of interest to understand regulatory signaling mechanisms, and changes therein, for genes whose activities are related to particular states of embryonic development or differentiation. I propose to investigate members of a multigene family, encoding histones, that are subject to distinct modes of transcriptional regulation during oogenesis and early embryonic development. This gene family provides a convenient model to examine the control of gene expression in embryonic development since they are among the first to be activated in many animal embryos. The major goals of this proposal are to elucidate the gene-proximal regulatory signal required for histone gene transcription early in embryogenesis, to investigate a regulatory transition in histone gene transcription during early embryonic development and to explore the mechanisms underlying the coordinate transcription of representative members of this gene family.